Correction of Nonlinear Digital Fringe Error for 3D Shape Measurement

• Main Authors: Wen-Zhao Huang, 黃文昭
• Other Authors: 鍾添東
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/16813645494497655173

碩士 === 國立臺灣大學 === 機械工程學研究所 === 94 === This thesis studies an error correction method to reduce nonlinear fringe errors induced by the LCD projector and digital cameras for measuring 3D shapes of objects. Firstly, an intensity look-up table is established for storing the difference between the assigned projected intensities and the measured intensities, and a phase error look-up table is also established for correcting the phase error induced by the intensity inconsistencies. Then, both intensity correction and phase error compensation are carried out for reconstruction of 3D object shapes, and the results between the uncorrected and corrected shapes are compared. It shows that the phase error compensation can effectively reduce the periodic fringe noise, and the intensity correction can improve the local splits on the reconstructed 3D shapes. Finally, by combining the advantages of the intensity correction and the phase error compensation, contrast-guided intensity correction and residual phase error compensation are proposed. 3D object shapes of several specimens with different colors and materials are measured. The results demonstrate that the proposed advanced error correction strategy offers good feasibility for improving the quality of reconstructed 3D shapes.